Chances are that if you set up an Apache web server on Mint or Ubuntu, you will see this error:

Could not reliably determine the server’s fully qualified domain name, using for ServerName

There are a couple ways to do it, however I think this is the “right” way to do it. The other common way involves creating what is essentially the old configuration file and pointing the new file to it. This one just uses the existing file to accomplish the same.

Open apache2.conf for editing:

sudo vim /etc/apache2/apache2.conf

Type in the following (I chose the end of the file):

ServerName localhost

This is just fine for 99% of home users.

Restart Apache:

sudo service apache2 restart

Presto! No more error.